1. Field of the Invention
The present invention relates generally to wireless telephones, and more particularly, to an electro-acoustic apparatus in a wireless telephone.
2. Related Art
A wireless telephone capable of supporting voice band communication typically includes a mouthpiece for transducing a first acoustic signal from a user into a first electrical signal, and an earpiece for transducing a second electrical signal into a second acoustic signal. The mouthpiece and earpiece together form an electro-acoustic portion (also referred to as the “electro-acoustics”) of the wireless telephone. During voice band communication, the wireless telephone user perceives a voice quality determined in part by a voice band frequency response of the electro-acoustic portion of the telephone. Typically, the wider the voice band frequency response, the better the perceived voice quality.
A conventional wireless telephone supports voice band communication limited to an audio frequency range of 300 Hertz (Hz) to 3400 Hz, in accordance with present Public Switched Telephone Network (PSTN) voice band limitations. Thus, the electro-acoustic portion of such a conventional wireless telephone typically has a voice band frequency response similarly limited to the frequency range of 300 Hz to 3400 Hz. That is, the conventional mouthpiece is likely to have an effective frequency response or “passband” limited to the range of 300 Hz to 3400 Hz, as is the conventional earpiece. The limited frequency response results in correspondingly limited or constrained voice quality.
It is generally desirable to improve the above-mentioned limited voice quality associated with a conventional wireless telephone. Thus, there is a need to improve/increase the audio frequency response of an electro-acoustic apparatus used in a wireless telephone compared to the conventional wireless telephone.